This invention relates to infant support devices and more particularly relates to a novel and improved displacement mechanism adapted for attachment to the resilient frame of an infant seat to selectively impart bouncing or vibratory action to the device.
We have previously devised a displacement mechanism for infant seats in which the displacement mechanism is mounted on the base portion and includes a variable speed motor drive which can be adjusted to tune the frequency of reciprocal motion of the base to the natural frequency of the seat for a particular weight baby and reference is made to the above-identified application for patent Ser. No. 09/436,697.
Other approaches have been taken to bouncing or rocker devices for infant seats and, for example, reference is made to U.S. Pat. No. 5,107,555 to M. L. Thrasher which discloses a crib rocking assembly having a mattress that rests on a plate which is connected to a rocking assembly that can move a mattress in a vertical direction. U.S. Pat. No. 4,985,949 to R. F. Jantz discloses an infant carrier seat rocker having a vertically oscillating lifter yoke. U.S. Pat. No. 5,860,698 to L. Asenstorfer et al discloses a rocker drive for child recliners with a musical clock that automatically operates when a rocker drive is activated. Other representative patents of interest in this field are U.S. Pat. No. 3,235,306 to V. A. Chernivsky, U.S. Pat. No. 4,141,095 to K. Adachi, U.S. Pat. No. 5,207,478 to T. B. Freese et al, U.S. Pat. No. 5,368,361 to C. Wen-Ming, U.S. Pat. No. 5,411,315 to M. H. Greenwood, U.S. Pat. No. 5,460,430 to C. W. Miga, Jr. et al, U.S. Pat. No. 5,503,458 to A. J. Petrie, U.S. Pat. No. 5,509,721 to L. C. Huang and U.S. Pat. No. 5,572,903 to Y. S. Lee.
In our prior device, emphasis was placed on physical displacement of a portion of the seat assembly such that the speed, frequency and distance of displacement could be controlled in relation to the weight of the infant. In accordance with the present invention, a similar result can be achieved by the suspension of an eccentric mass of one or more different selected weights on the infant seat in such a way as to impart relatively high frequency of vibration with a low amplitude of displacement or relatively low frequency of vibration with a high amplitude of displacement; and further to impart optimum vibration or bouncing to the seat which, in a simplified manner, can be tuned to the natural frequency of the seat according to the weight of the baby.
It is therefore an object of the present invention to provide for a novel and improved method and means for imparting bouncing or vibration, or a combination of selectively bouncing and vibration, to an infant seat.
It is another object of the present invention to provide for a novel and improved mechanism for selectively imparting bouncing to an infant seat which can be selectively tuned to the natural frequency of the seat according to the weight of a baby placed therein.
It is a further object of the present invention to provide for a novel and improved infant seat assembly in which the bouncing and/or vibration of the seat is greatly enhanced by mounting of the mechanism to the seat so as to be most sensitive to the weight of the baby.
An additional object of the present invention is to provide for a novel and improved mechanism for selectively bouncing or vibrating an infant seat for babies and for selectively shifting between high and low speed vibration in combination with high and low amplitude of displacement which is characterized by its simplicity, ease of manufacture and its conformability for use with different types of resilient frame infant seats.
In accordance with the present invention, there has been devised a novel seat-vibrating mechanism which is specifically adaptable for use with infant seats but nevertheless is also conformable for use with other resilient frame supports, such as, for example, a cot or bed. It is therefore desirable to provide a vibrational mechanism which is essentially stand-alone or self-contained so as to be attachable to various articles of furniture. In its application to an infant seat or other resilient frame support, the vibrational mechanism is drivingly connected to the frame and includes means for vertically reciprocating the frame to impart a vibrating motion thereto. Furthermore, in its preferred application, the vibrational mechanism is employed in association with a foot rest or other cantilever support portion rigidly connected to the resilient frame such that vibration is imparted via the cantilever support into the resilient frame. The vibrational mechanism and specifically the means for reciprocating or vibrating the resilient frame includes adjusting means for regulating the frequency of vibration of the frame whereby to tune it to the natural frequency of vibration of the frame depending upon the weight of the infant. When the vibrational mechanism is adjusted to match the natural frequency of the frame, with an infant in place, the amplitude of displacement is enhanced and the power necessary to maintain a given amount of displacement or motion is reduced. The vibrating mechanism is preferably comprised of motor drive means employed in association with one or more eccentric weights of different mass and shifter means for selectively connecting the motor drive means to one of the eccentric weight members. In order to adjust the frequency of vibration imparted to the frame, the adjusting means may take the form of a rheostat which is manually adjustable and regulates the speed of rotation of a motor drive shaft off of the motor drive means.
An additional feature of the present invention resides in the use of a step-down speed changer off of the motor drive to regulate the speed of rotation of a relatively lightweight eccentric mass to impart slight vibration to the frame. The shift means may be employed to alternatively connect the motor drive means into a relatively heavy weight eccentric mass mounted on a separate drive shaft with a speed reducer interposed between the motor drive means and the heavy weight mass so as to create a much lower frequency of vibration and higher amplitude of motion for a given speed of the motor.
The above and other objects, advantages and features of the present invention will become more readily appreciated and understood from a consideration of the following detailed description of preferred and modified forms of the present invention when taken together with the accompanying drawings in which: